


Heat Wave

by allidoissin



Category: Undertale (Video Game)
Genre: Blow Jobs, DomPapyrus, Ecto-Penis (Undertale), Ecto-Tongue (Undertale), Ecto-Vagina (Undertale), Established Relationship, Fluffy Smut, Fontcest, I Don't Even Know, M/M, Mating Cycles/In Heat, Overstimulation, Plot What Plot/Porn Without Plot, Sans knew what he was getting into, SubSans, after the resets, forced orgasms?, not really tho, surface fucking, tiny hint of dub-con at end of chapter 2?
Language: English
Status: Completed
Published: 2017-04-13
Updated: 2017-04-24
Packaged: 2018-10-18 07:20:14
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 7,285
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10611981
Author URL: https://archiveofourown.org/users/allidoissin/pseuds/allidoissin
Summary: Sans goes into heat and needs Papyrus to fuck him into oblivion. That's pretty much it. More fluffy smut! (I suck at titles).Ch. 2 - Papyrus goes into heat... and fucks Sans into oblivion. Hurhurhur...





	1. Chapter 1

**Author's Note:**

> Writing Sans getting absolutely wrecked sexually by Papyrus makes my dick hard. I don't fucking know, just let it happen...  
> I have a tumblr now, nothing much is there atm but I hope to change that in the future: https://allidoissinfam.tumblr.com/  
> Commence the sinning!

Sans woke with a start, a sheen of sweat already slicking his ivory bones. It wasn’t a nightmare that jolted him back to consciousness on the couch causing the soft fleece blanket to fall from his shoulders and bundle around him. Warmth coiled loosely through his frame, settling comfortably in his middle and stirring his magic with arousal, completely unmistakable for the signs of heat.

He thought he had felt a little off this morning when he first woke and saw Papyrus off to his job. His magic had seemed restless and a blue tinge had dusted his cheekbones for the better part of the day. Fearing he might be coming down with some sort of monster based illness Sans had opted to take a day off, drink plenty of fluids and nap on the couch, which suited him just fine.

Another wave of arousal gently washed through him, making him groan and quickly stagger to his feet. He rubbed at his face forlornly before teleporting to his and Papyrus’ shared bedroom, shucking off his hoodie and tank top and throwing himself onto the bed. He panted lightly and ghosted a hand over his ribs, trembling at the sensation while his other hand hurriedly dug his phone from his shorts pocket. Checking the time he groaned again and furrowed his brows in exasperation.

Papyrus wouldn’t be home for another three hours and that was _if_ the restaurant wasn’t too busy today. Of course his heat had to start when Papyrus wasn’t here. He let out a small whimper as another pang of lust shot through him, more pronounced than the ones before. His magic was quickly flooding into his pelvic cavity, demanding attention but remaining unformed from lack of stimulation at the moment. With one hand Sans began shimmying out of his shorts, hissing as cool air brushed across his heated pelvic bones, his other occupied with texting his brother.

               **any chance of you getting off early?**

Sans kicked his shorts the rest of the way off, his heat hazed mind not giving a flying fuck where they landed. He dropped his phone onto the mattress, desperately awaiting the chirp of a reply and clenched his hands into the plush comforter beneath him. He hissed when his magic pulsed again, his hips unconsciously bucking into the air for any kind of stimulus. If he started masturbating now he knew he wouldn’t be able to stop until his heat was thoroughly dealt with and without Papyrus’ help that would be a long ass time. He needed to stay at least semi coherent so he could message his brother and hopefully-

A sharp ding snapped him from his thoughts and sent him scrambling for his phone, cursing any accidental touching of his hyper-sensitive bones.

               I don’t think so brother! We r vry busy today! Might have 2 stay late

No no no. That can’t happen. He was not suffering through the first part of his heat alone, he would go insane! Sans knew his fuddled mind was overreacting, heats weren’t _that_ bad. His first one had been by himself and he had survived that, but now his magic seemed to recognize that he had a long-term mate and it positively _yearned_ for him.

**need yur help. a little heated over here if you get me**

There. Short, sweet, and to the point. There was no way Papyrus could misinterpret-

               Is the ac out again? You know more about fixing it than I do

No no NO! Sans’ hand trailed across his femur and drifted toward his pubic bones drawing a long suffering moan from his parted teeth.

“c’mon paps,” Sans whimpered and furiously typed a new message with one hand while the other struggled to stay away from the coiling magic in his pelvis.

               **nope. plz come home its super HOT here**

Uppercase letters! How much more of a hint did he need! Sans groaned loudly and shuddered as another wave of unheeded pleasure coursed through him. Through sheer force of will he managed to snap his wandering hand back onto the comforter and clenched his digits roughly into the fabric. After an agonizing 20 seconds another ding sang cheerfully from his cellular device as if mocking his current predicament.

               Sans whats wrong?

The small skeleton monster had to fight the urge to grab a pillow and scream into it. He loved his brother to death but sometimes… Sans clenched his teeth and typed up one last message.

               **I NEED YOU TO FUCK ME**

His cheek bones burned with arousal and slight embarrassment from the bluntness of the text. Hopefully Papyrus was not allowing his coworkers to read over his shoulder or anything. Sans’ eyesockets slid closed, his free hand wandering back to caress the inside of his femur. He could only imagine the surprised look on Papyrus’ face at that last text which caused his perpetual grin to quirk up even further.

His hand slid more firmly over his femur, drawing a groan from his parted teeth as he imagined his brother’s bewildered expression. His face would probably be lit up with his orange magic as he came to understand Sans’ predicament, before his eyesockets would become lidded with his own arousal. He imagined Papyrus rushing home and bursting through the bedroom door, eager to place his hands on Sans’ sensitive bones. Those phalanges would carefully, intimately slide over his ribs, making him squirm and beg for more. Sans began to openly pant as he thought about his brother’s touch drifting lower and lower, his own hand finally meeting the blue mist of shapeless magic in his pelvis. The magic sparked and writhed excitedly, finally achieving the stimulation it so desperately needed and formed a slick, clenching entrance.

Sans practically whimpered when his fingers brushed against the puffy lips, sliding through the folds and gently massaging his newly formed clitoris. Pleasure coiled fast and hot through his heaving frame as he sped up his motions. Thoughts of Papyrus touching him, his long orange tongue delving deep inside, his cock pounding into him mercilessly-

His climax hit him embarrassingly fast, causing the small skeleton monster to let out a cry and arch his back against the bed, slowing his phalanges gradually to ride out his first orgasm. He relaxed back into the pillows and let out a sigh of contentment, his heat momentarily abated for at least the next few minutes. A sudden ding of his phone jerked him from his reverie, the new message lighting up his grin and filling him with a new wave of warmth.

               Omw

Thank God. Sans settled further into the comforter, relaxing a bit before the next inevitable wave of arousal would turn him into a wanton mess. He could probably get off at least two more times before Papyrus would finally arrive but he knew he would be far from done. By himself his heats could last for ten hours or more but with his lover’s help that timeframe was drastically reduced. Sans found himself thanking his lucky stars that Papyrus had as much stamina as he did.

With his thoughts constantly revolving around his brother heat began to seep into his bones again, lust steadily building within him. Sans sighed and nestled deeper into the plush pillows at his back. _Here we go again._

\----------------------------------------------------------

Papyrus made record time driving back home, possibly even breaking a few speed limits in his haste to help his brother with his ‘problem’. He felt a little guilty about claiming that Sans had come down with a sudden illness at work and needed the utmost care and attention from his brother, The Great Papyrus, but the restaurant had been adequately staffed today and the owner had allowed the eccentric skeleton monster to leave.

As he pulled up in front of the house Papyrus quickly rushed inside and took the stairs two at a time toward the bedroom. He could smell the alluring scent of Sans’ heat as he drew closer, sweet and slightly musky, causing Papyrus’ magic to rapidly pool into his lower anatomy. His hand reached for the doorknob to their shared bedroom, pausing just long enough to listen to Sans’ debauched moans and gasps on the other side.

Magic burning hotly in his pelvis, Papyrus turned the doorknob and opened the door slowly, freezing at the sight before him. Sans was completely nude and spread out on the bed, one hand behind his head grasping at the pillows, the other buried between his femurs, desperately rubbing himself to completion. A blue blush painted his flushed face, his mouth open and cyan tongue hanging out in a feverishly lewd manner. At the sound of the door opening his eyesockets snapped open and two hazy eyelights flickered to focus on Papyrus’ enraptured face.

Sans toppled over the edge of yet another climax, moaning Papyrus’ name long and loud and canting his hips into the air. Papyrus stared at the erotic display with wide eyesockets. At the obvious peak of his brother’s pleasure Papyrus’ magic had flared and formed into a hard shaft in his work pants, the subsequent moan of his name sending a jolt of pleasure down his spine. Sans looked stunning splayed out on the bed as he was, twitching and moaning his brother’s name in desperate need.

Papyrus closed the distance between the two swiftly, leaning over his panting brother and planting his hands to either sides of Sans’ head. Sans’ eyelids fluttered when Papyrus leaned down and clicked their mandibles together in a kiss, his orange tongue swiping across the smaller skeleton’s teeth in request. Sans moaned and met his brother’s conjured muscle with his own, savoring the slide of their sparking magic against each other and wrapping his arms around his lover’s neck.

Papyrus drew back far enough to fix Sans with a heated look, his hands moving to gently fondle the alabaster expanse of ribs beneath him. “How many times have you cum?” the taller skeleton asked, his eyesockets becoming hooded when he drew a pleased whimper from Sans. His normally boisterous voice had dropped in both volume and pitch with his arousal, making Sans shudder beneath him.

“hah, uh… that l-last one makes, ahn, f-four i think,” Sans stuttered, his brother’s ministrations to his ribs turning his mind to putty. Even suffering from heat he usually needed several minutes in between orgasms to prepare for the next round, his refractory period increasing after each one. However, Papyrus’ presence and insistent touches had his magic flaring and pulsing, his pussy clenching and begging to be filled.

“f-fuck paps, please, i need you,” Sans gasped as Papyrus’ phalanges drifted lower, one hand stroking gently down his spinal column, the other trailing lightly over his ilium. The larger skeleton monster only grinned at his brother’s desperate pleas, bending forward to lathe Sans’ sternum with his tongue. Papyrus’ mouth began to drift lower as he nipped and licked his way further down, moving his body onto the bed over the writhing, gasping monster. His hands had settled to a stop at Sans’ hips, gently grasping his pelvis to keep the smaller skeleton from moving too much while his tongue and teeth continued their quest to reach their prize.

Papyrus nestled his skull between his brother’s femurs, spreading them apart slightly and allowing his mouth to water at the beautiful way Sans’ conjured genitals flowered perfectly before him. Taking pity on the whimpering monster he leaned forward and drew his tongue through the thick folds, groaning at the intoxicating taste of his brother’s magic. Sans jerked and gasped at that first swipe, the heated muscle sending shockwaves of ecstasy rippling through his tense frame. Papyrus marginally increased his grip on Sans’ hips and attacked his pussy with renewed fervor, his tongue lapping at the engorged clit with the passion of a man starved. The smaller skeleton barked out a choked cry at the onslaught of sensation and surged up to fold himself over his brother’s skull, his hands scrabbling at the back of Papyrus’ work shirt in a desperate attempt to ground himself.

Holy fuck, this was so much better than anything he could do to himself. Tears of pleasure pricked the edges of Sans’ clamped eyesockets while unbidden moans and cries of pleasure fell from his slack mandible. At the rate his brother was going his orgasm was building almost embarrassingly fast again. Papyrus released his hold on one of Sans’ hips to lightly finger his throbbing entrance, easily pushing two long digits inside. He curled the digits carefully in a ‘come hither’ motion, rubbing perfectly against the bundle of nerves that would hurtle his brother to completion. The larger monster was rewarded with a loud shout of pleasure from Sans before his hips twitched and canted urgently into Papyrus’ face, flooding his mouth with his tart release. Papyrus feasted on his arousal with aplomb, his own lust building from the sinful sounds he managed to wring from his brother’s mouth.

Sans collapsed back onto the bed as Papyrus continued to lap up any remaining juices that flowed from his pussy, jerking and moaning at the overwhelming sensations. Papyrus finally drew back with an audible slurp, drawing his tongue across his teeth to clear away the blue tinged slick from his brother’s release. His eyesockets softening, he gazed at the debauched form of Sans spread out over the comforter, sockets half-lidded and panting harshly as tremors of aftershocks made his hips twitch intermittently. A sense of pride filled his soul at the thought that _he_ did this, _he_ was the only one that could do this to Sans. _He_ was the one that Sans had chosen to share himself with.

Sliding off the bed, Papyrus began to shed his work shirt, pants and any other articles of clothing he had been wearing, tossing them into the laundry hamper by the door. His throbbing erection had not abated in the slightest and stood proud from his pelvis, casting a gentle orange glow onto his own ivory bones. He turned back around to view Sans staring at him with hooded sockets and eyelights that were reminiscent of hearts.

Papyrus smiled warmly at his lover and made his way back onto the bed, gathering the smaller monster in his arms and placing a kiss on the crown of his skull. Sans sighed with pleasure, nuzzling his head into his brother’s clavicle. The larger skeleton ran his hand over the other’s spine in a soothing motion, content to allow Sans a few minutes of rest before the next round. Soon enough he sensed Sans’ magic spiking, his face flushing again with carnal need.

“Ready to go again?” Papyrus said.

“hell yeah,” Sans murmured, lifting his head to capture his brother’s mouth in a deep kiss. Papyrus groaned into the kiss, shuddering when Sans ground his hips against his own causing his still present erection to slide against the slick lips of his brother’s pussy. Papyrus broke the kiss to rise to his knees, turning his brother so his spine rested against his chest and Sans’ arms wrapped around his neck. He grasped Sans’ spread femurs and positioned his soaked entrance directly over his pulsing cock, relishing the shivers of anticipation coming from the smaller monster.

Papyrus placed a kiss to the side of his brother’s head, gently lowering him down until the tip of his member was swallowed by Sans’ tight, wet heat. “I love you,” Papyrus whispered before he suddenly snapped his hips up to hilt completely within his lover’s passage. Sans cried out at the force of the thrust, jerking and resting the back of his skull on Papyrus’ shoulder. Fully embedded in his brother’s magic Papyrus groaned loudly at the feeling of hot, slick, fluttering walls currently surrounding his member.

With perfect access to his sensitive cervical vertebrae the larger skeleton lathed the bones of Sans’ neck with his tongue, pulling his cock slowly from his pussy and slamming back in again. The slow withdrawal followed by quick thrusts was making Sans crazy, his magic writhing and practically begging for more.

“f-fuck paps, please… fasstterrr,” Sans whined, fixing his brother with a pitiful look from his watery eyesockets. Papyrus graciously obliged, gradually pumping his hips to a quicker pace, dragging more and more positively sinful moans and cries from Sans’ gaping mouth. The slick sounds of his cock repeatedly invading his brother’s pussy along with the clack of bone meeting had pleasure rapidly curling through his pelvis and spine, urging him on.

“God Sans, you feel incredible,” Papyrus moaned in between planting skeleton kisses on what he could reach of Sans’ clavicle and neck. “I want you to cum around my cock… I want to fill you with my cum, make you beg and plead and scream for me to f-fuck you harder.”

The words Papyrus was muttering into his nonexistent ears had Sans blushing far more profusely than before and igniting his entire frame with a burning ecstasy only Papyrus could provide. Dirty talk was not a common occurrence for the taller skeleton but damn if it didn’t do the trick. Sans could only babble back incoherently, phrases of _I love you_ , _you’re perfect_ , and _right there!_ mixing into disjointed syllables that spilled from his mouth. He tightened his grip on his brother’s neck, arching his spine as Papyrus fucked him hard and fast, his cock continuously sliding over the bundle of nerves nestled deep in his pussy that had him seeing stars.

Sans’ choked wail signaled the rush of his climax, his walls clamping down tightly on the thick cock that pounded into him. Blinding ecstasy flooded his locked frame, shorting out his eyelights and further coating Papyrus’ member in the blue tinged juices of his release. Papyrus gasped as his brother’s pussy constricted around him, intense pleasure spurring him to thrust into the undulating heat and dragging out Sans’ orgasm for as long as possible. He gradually slowed to a stop when Sans’ hands slid from his neck to fall limply to his sides.

Papyrus released his hold on his brother’s femurs, positioning the smaller monster’s kneecaps on the bed and placing one hand on his sternum to gently lower the top half of his body to rest on the comforter. Sans moaned beneath him, aftershocks of his most recent orgasm still coursing through him in waves, his hands weakly grasping at the fabric pressed to his cheek. Some still slightly coherent part of his brain realized that Papyrus had yet to pull out. He twitched when his brother ran his phalanges over the back of his spine, resting both hands against his hips and grasping firmly. Papyrus hadn’t cum yet… oh fuck.

Papyrus shifted his hips moderately, pulling his member from Sans’ grasping entrance and slamming back in again, over and over. He tore a _scream_ , a full blown scream from his brother’s open mouth, the sound of Sans’ overwhelming pleasure causing his cock to twitch. The taller skeleton monster folded himself over his smaller lover, biting and licking at his exposed shoulder blades and never once losing the harsh and fast pace his hips set. Sans writhed and shuddered beneath the onslaught, his desperate cries building in pitch with every thrust.

Suddenly he was cumming again, flooding his pulsing channel with fluids which were quickly displaced by Papyrus’ frantic thrusts. His cum leaked from around his brother’s cock, splattering onto the comforter below, staining the gray fabric with blue. Tears of pleasure fell from his clamped eyesockets, mouth open in a perpetual ‘o’, drool and debauched noises that he himself couldn’t even comprehend spilling forth.

At the surge of Sans’ latest climax, Papyrus’ hips began to stutter as he chased his own release. The heat from his brother’s pussy, so wet and slick against his cock had him panting and groaning with need. He was so close but he had to be sure Sans was well taken care of. He curled one hand in between Sans’ shuddering femurs, his phalanges questing until they found the engorged nub of his brother’s overstimulated clitoris. He rubbed at the sensitive button, wrenching a shriek from his lover before Sans’ walls were clamping once again around his thick member. Another gush of liquid heat surrounding his cock finally had Papyrus gasping and rutting himself a few more times into the pliant magic, his own climax sending spurts of his cum to coat the quivering walls.

Both monsters stilled completely, broken gasps and groans of pleasure drifting from panting mouths. Papyrus leaned forward, lightly kissing up his brother’s spine and neck before gently pulling his cock from Sans’ pussy. He watched as his orange tinted cum dribbled from the swollen lips with hooded rapture, his soul swelling again with pride. His gaze drifted further, taking in the absolutely wrecked form of his lover who had collapsed fully onto the bed, quiet pants escaping his parted teeth. Sans’ magic gradually lessened, his conjured pussy disappearing but the coiling blue mist in his pelvic girdle still remained.

On shaking legs Papyrus moved off of the bed and grabbed a robe from the bathroom, wrapping the fluffy material around himself. That many successive orgasms in a row probably bought him at least 30 minutes to rest until Sans would be ready to go again. He made his way downstairs and into the kitchen, gathering up an armful of healthy (and unhealthy) snack foods (and a bottle of ketchup) for both himself and his lover. He knew Sans would likely be starving and in need of energy when he regained enough composure from this last bout. Papyrus wandered back into the bedroom, depositing the snacks onto the nightstand and crawling back onto the bed.

He carefully gathered the slack bones of his brother’s form into a loose hug, settling them both down to lay beside each other against the fabric. Sans’ eyelids fluttered open, his eyelights reigniting into shapes that definitely looked like hearts when he caught Papyrus’ gaze.

“have i ever told you how amazing you are,” he muttered tiredly, burrowing closer to his brother’s warmth and threading his phalanges through his ribs. Papyrus nearly purred with contentment and let out a soft _nyeh heh heh_ at the sentiment.

“Almost daily dear brother!” Papyrus trilled. Sans mumbled something incomprehensible, his eyelids fluttering shut as he fell into a light doze. Papyrus only smiled and gently rubbed the others spine. As much as he enjoyed work, these next few hours would be far more fun.


	2. Chapter 2

**Notes for the Chapter:**

> Sorry this took so long. Got a Switch and started playing Zelda... so good. Anywho, enjoy!  
> allidoissinfam.tumblr.com - Come visit me!

It’s the middle of the night when Papyrus wakes. That isn’t such a big deal since he doesn’t require a lot of sleep to begin with, but the heady feeling of magic pressing at his joints sends conflicting urges through his soul. His body feels achy and heavy, excess magic building up and simmering just beneath the surface. The kind of magic build up that needs to be worked through… rather physically. Part of him just wants to drift back to unconsciousness and ignore the currently unpleasant tingling in his bones but he knows that would be futile.

Papyrus sighed and sat up in bed, wincing slightly when the sheets brushed against his bones. They were quickly becoming overly sensitive to touch, a signature of the rapid onset of his heat. He glanced to his left, taking in the curled form of Sans nestled under the covers whose soft snores escaped his parted jaw along with a thin line of drool streaking his lower mandible. Papyrus couldn’t help but smile at the sight.

When they first came to the surface (and even before that) Sans had been almost constantly plagued by terrible night terrors, inhibiting him from getting a decent night’s sleep. Papyrus figured that was why he would often find the smaller skeleton passed out at his sentry station underground, his skull pillowed by his arms and obnoxious snoring drifting through the chilly Snowdin air. Seeing his older brother sleeping so peacefully now warmed his soul immensely, sending a pulse of affection through the culmination of his being.

Sans shifted in his sleep, a soft noise that sounded dangerously like a moan sneaking past his canines before he quieted and stilled, burrowing deeper into the warm bedding. Papyrus started at the sound. He found himself staring at his smaller lover’s form, his phalanges itching to touch his smooth femurs, run his fingers over Sans’ spine, drag noises of pleasure from his slack mandible. He shook his head to try and clear the lewd thoughts from his mind and noticed a familiar orange glow coming from his pelvic region. Stripping the rest of the covers from his lanky frame revealed his cock tenting the fabric of his pajama pants, already formed and half hard at just the thought of Sans. Papyrus stifled a groan and flited his eyesockets to the glowing red digits of the alarm clock on the bedside table. It was far too early to wake Sans for help, especially when the monster was so deeply and peacefully asleep.

Papyrus sighed once again and slipped quietly from the bed, padding softly across the room to the bathroom door. He slipped inside, gently shutting the door before turning the light on so as not to disturb his brother. A wave of arousal shimmered through him, making him shudder and barely suppress a moan of desire. Hopefully a cold shower would be enough to curb his insistent urges until his brother was properly awake.

The tall skeleton monster peeled off his clothing from sweat-slicked bones, folding them neatly and placing them on the lid of the toilet before turning the shower on to the coldest setting. Stepping into the spray had him flinching and biting back a yelp as the frigid water hit his heated bones. He quickly adjusted the temperature to a slightly more comfortable level, still cold but not as bad as before.  After a minute or so of letting the water sluice over his body, seeping into the discs of his neck and spine, his arousal still raged through him, even stronger than before. This wasn’t working.

His thoughts kept returning to his sleeping brother and the way his magic would light up his cheeks with blue whenever Papyrus would wrap him in a hug and tell him he loved him. The way his grin would widen impossibly further when he finally got Papyrus to laugh at one of his ridiculous puns. The way he would curl his body into Papyrus’ chest, slotting perfectly together like a puzzle piece as they both drifted off to sleep at night. The way his ribs would heave with gasps and moans of pleasure, spread out beneath him like a glorious feast.

Papyrus groaned lowly, his orgasm washing over him like an intense wave of relief. He snapped his eyesockets open (when did he shut them?). He had one hand placed on the cool tile of the shower wall, the other stroking gently over his throbbing length, squeezing any last remaining tingles of pleasure from the sensitive magic. When had he even started jacking off (as Sans so eloquently called it) in the shower? When he started thinking about Sans of course. A smile bloomed across his mandible as he thought about how irrevocably smitten he was, had been for a long while now.

Pleasure pulsed through him continuously, his member still remaining hard in his grasp. He stroked the magical construct, rolling his thumb over the head spreading the cum from his earlier release around the tip. His heat-addled mind denied any thoughts of shame or modesty to manifest, only allowing him to focus on his current problem and how to remedy it. He groaned again, picking up the pace of his stroking hand, wishing it was Sans’ hands giving him pleasure… or his mouth… or cunt. Flushing orange, he reached his peak twice more in the shower before finally shutting off the water while he still possessed some rationality. His heat hadn’t abated in the slightest and if he kept going like he was their water bill would be at an all-time high.

Somehow he managed to keep his hands away from his cock long enough to gingerly towel down and wrap the fabric around his waist, twitching at any physical contact he accidentally (or purposefully) administered to himself. When his heat arrived it did so hard and fast. Rational thought quickly became a struggle for the tall skeleton monster, the magic that kept him functioning wanting nothing more than to bond with its ‘mate’.

“was wondering why you were showering at 3:36 in the morning.”

Papyrus stopped short once he left the bathroom, Sans’ voice snapping his attention to the smaller skeleton sitting up on the bed. Sans’ eyelights held a hint of mirth as they swept over his tall frame, taking in the orange flush that dusted his face and the obvious evidence of his arousal through the thin white towel. Papyrus couldn’t even respond properly, just whimper with pained need. Sans was awake!  - and hopefully willing to help.

The smaller skeleton monster just chuckled and motioned him over, a glint of lust briefly flashing in his eyesockets. “c’mere paps.”

Papyrus immediately stalked towards him, closing the distance between the two swiftly and clacking their teeth together in a kiss. His tongue manifested, swiping across Sans’ teeth which immediately granted entry. As their tongues entwined and slid across each other Papyrus deepened the kiss, swallowing the little mewls of pleasure his brother produced. His hands were everywhere, brushing across the tank top Sans was wearing and dipping underneath to fondle the ribs below, dancing across the hem of his boxers to stroke an exposed ilium.

“p-paps wait,” Sans panted, pulling back far enough to place his hands on Papyrus’ exposed chest. Papyrus drew back with a whine.

“Sans please! I-I need you to-” he managed to grind out, his heat-riddled mind somehow allowing speech.

“i know paps, i know,” Sans chuckled. He slid off the bed and reversed their positions, sitting Papyrus down on the edge of the mattress and kneeling between his legs. “if we get to the main event too soon i won’t be able to keep up.”

Papyrus groaned at the sultry tone of his brother’s voice and the way his hooded eyesockets peered up at him. Sans ran his phalanges up the exposed bones of Papyrus’ lower legs, caressing the inner parts of his tibia and fibula before working his way up to his femurs. It took all of the taller skeleton’s willpower to keep his hands fisted in the comforter below him as his body twitched and shuddered at every little touch Sans graced him with. Sans gently unwrapped the towel around from Papyrus’ waist, eyeing the glowing, orange erection with rapt interest.

He curled one hand around the base of Papyrus’ cock, grinning at the choked sound of pleasure it dragged from his mandible. Sans stroked slowly upward and downward, alternating the pressure with each pass. He thumbed the tip of his member, pressing down lightly at the opening before resuming his stroking at a faster pace.

“P-please Sans,” Papyrus whined, his eyelids falling closed in response to the overwhelming stimulation. “I’m so c-close!”

Sans increased the speed of his hand even more, staring up at Papyrus’ pinched face. “cum for me paps.”

Papyrus’ hips jerked as his climax hit. He cried out in pleasure as wave after wave of ecstasy rushed through him, drawn out by Sans’ continuously moving hand. His release came in spurts, covering the smaller monster’s digits and some even landing on his tank top. Sans didn’t seem to mind in the least though. He withdrew his hand from around his member and made a show of licking the translucent orange fluids from his phalanges, reveling in the barely suppressed groan of need the action dragged from his younger brother.

Without giving him time to recover (not that he needed it anyway) Sans dropped his hands back to Papyrus’ femurs and leaned forward to drag his tongue up the still hardened shaft. Papyrus yelped at the change in heat and texture, his hips thrusting towards the source in a vain attempt for more. Sans did not disappoint, in fact he opened his jaw wide and took his whole length into his mouth. He lined the inside of his jaw with the soft, wet warmth of magic and conjured a passage comparable to a human throat to wrap around the pulsing cock.

Papyrus could not hold back the shocked cry of pleasure that escaped him at the sudden change. This was _heaven_. His hands jerked up to grasp at the sides of his brother’s skull, pressing lightly but insistently against the smooth bone. Sans hummed contentedly around his cock, if possible sending even more shockwaves of pleasure pulsing through his magic. Then Sans started moving. Slowly at first, bobbing his head up and down, his tongue continuously coiling and sliding around the hard construct nestled in his jaws. Papyrus whimpered and moaned encouragements, pleasure coiling tighter and tighter in his middle as his release drew near. Sans hummed again causing the conjured magic in his mouth to undulate around his cock.

With just a few more bobs of Sans’ head Papyrus came again, spurts of his cum shooting forth and hitting the back of his brother’s mouth and conjured throat. Sans continued the movements of his tongue, greedily swallowing down the other’s ample release. But he didn’t _stop_. The sucking motion continued around his overstimulated cock, making his hips twitch and jerk in Sans’ grasp.

“Ahhhnn Sans!” Papyrus gasped and writhed under his brother’s heated ministrations, already on the verge of yet another climax. This was exactly what he needed, what his body was begging him for. His heats weren’t nearly as lengthy as Sans’ were. Where Sans could take several hours until he was satiated with long refractory periods in between, Papyrus’ heat was just a few hours of nearly _nonstop_ arousal. His magic didn’t seem to need much of a rest in between each mind-blowing orgasm, which was a blessing and a curse in a way. Sans had tried to explain it one time as he had a deeper pool of magic reserves therefore required more time to work through it, whereas Papyrus had less and was so naturally energetic that he burned through it faster.

Papyrus didn’t know, and right now didn’t care as another climax sent a jolt through his frame, Sans’ tongue not allowing him a reprieve. Panting harshly he fell back onto the bedspread, barely able to prop himself up on one elbow to watch his brother’s beautifully flushed face swallow his cock over and over again. Sans continued sucking him off, forcing two more borderline agonizing orgasms from his thoroughly spent member, each time swallowing down his release like it was a rare treat.

Finally, after delivering one last hard suck he released Papyrus’ member with a pop and rocked back on his heels. Papyrus fully collapsed back onto the bedspread, basking in the pleasant tremors of ecstasy that shimmered through his bones. With the edge of his heat taken off more rational awareness came back to the taller skeleton. He heard Sans shift and head toward the bathroom, probably to freshen up before returning to the bedside to check on his brother.

The absolutely content look on the younger’s face made Sans’ perpetual grin widen and a soft chuckle to escape his teeth. He eyed Papyrus’ pelvis noticing the softened member was already hardening up again, would soon be ready for more stimulation. Which was great because Sans had been sporting a throbbing pussy for the past fifteen minutes, a reaction of his magic responding to Papyrus’ heat.  He tapped on Papyrus’ sternum to get his attention, snickering at the bleary look he received as if rousing the other from a daydream.

“think you could sit against the headboard paps?”

Papyrus groaned but managed to comply with Sans’ request, dragging his body to lay correctly on the bed and relaxing back into the plush pillows. He watched as Sans stripped the rest of his clothing off, his heat once again surging as more and more of his brother’s snowy white bones were unveiled. Sans moved onto the mattress and crawled toward his younger brother making Papyrus shudder with renewed lust as he drew near.

“so,” Sans said, straddling the taller skeleton. A shudder gently rattled his bones when the slick lips of his pussy brushed against Papyrus’ waiting cock. “that a banana in your pocket or are you just happy to see me?”

“Sans, that’s not even-” Papyrus’ response was cut off as Sans wrapped his arms around the taller skeletons neck and drew him in for a deep kiss. His groan was swallowed when Sans shifted his hips, allowing the tip of his erection to slide into the welcoming heat of his brother’s aching pussy. The smaller monster sank slowly down, releasing breathless moans as inch by inch Papyrus’ cock was enveloped in his tight, wet heat.

Finally, after what seemed an eternity to Papyrus, Sans came to a stop, resting fully against the other’s pelvis. His forehead came to rest on Papyrus’ clavicle, shallow pants escaping from his parted jaws as his walls adjusted to the feeling of being filled. Was it just him or did Papyrus’ cock seem thicker than normal?

Before Papyrus could voice any complaints about lack of movement Sans began a torturously slow pace, raising his hips up until the tip of his brother’s member nearly left the grasping heat before sinking back down again just as slowly. He leaned back as he rode Papyrus, his own magic flushing his face and joints with a beautiful azure shade in his excitement. Papyrus shuddered beneath him, drinking in the sight and sounds of his lover in his lap. His heat was still going strong, demanding release in the most carnal way possible and this agonizingly languid pace was not going to cut it.

“S-sans… can I?” Papyrus practically moaned in want, raising his hands to grasp at his brother’s hips. Sans’ small nod was all he needed to take matters into his own hands, gradually increasing the speed with his own quick thrusts. Sans keened with pleasure at the faster pace, rolling his head back and moaning openly into the dark room, letting his tongue hang out lewdly. Papyrus panted and groaned beneath his brother as pleasure danced wildly through his frame but not coming to fruition fast enough. He could fix that.

Papyrus surged upward, grasping at Sans’ ribs and pushing him down on his spine on the mattress. He witnessed a glimpse of blown eyelights that quickly rolled to the back of his brother’s skull as Papyrus pumped him hard and fast, his heat retaking his mind and striving for the one thing it needed. Sans’ cries and gasps of ecstasy fueled him, making his magic burn hotter and his thrusts to grow faster, chasing that inexplicable feeling of release that drew closer by the second. He came hard, spurts of his cum hitting the back of Sans’ magic, mixing with the fluids that slicked his brother’s channel. He continued to thrust through his own orgasm, completely overwhelmed by the pleasure that coursed through his body and wouldn’t allow him to stop.

“f-fuck paps!” Sans wailed and arched his spine when Papyrus began rubbing jerky circles around his clitoris. “i-i’m gonna-” His words were cut short with a cry as his walls clamped down around the thrusting member inside him. Juices surged from his pussy in a hot gush, further coating Papyrus’ cock with his essence. Papyrus groaned loudly at the feeling of Sans’ orgasm around his oversensitive member. If the head he received earlier was heaven this was somehow way better. After a few more thrusts he bottomed out once again, spilling his seed into the convulsing passage with a shuddering moan.

Pulling out gently he watched as a mixture of their cum dribbled from his brother’s spent pussy. Sans’ hips twitched intermittently with the aftershocks of his climax, pants and quiet moans of pleasure drifted from his mouth. It was so… _alluring_. Papyrus’ magic burned for more. He wanted to impale his brother over and over again until he just plain couldn’t anymore. He wanted to make Sans cum so many times he begged for him to stop.

Papyrus rolled Sans onto his side, grasping his upper femur and spreading him wide before hilting himself fully within Sans’ conjured pussy once again. He fucked him harder and faster, dragging orgasm after orgasm from the pliant magic beneath him as well as his own. He changed position often, taking his brother from behind, on his side, with Sans’ spine pressed to his chest and his femurs parted widely to allow for optimal pleasure. Every gasp, moan, and scream of ecstasy he managed to rip from Sans’ mouth was like music to his ears.

He finally began to slow when he felt Sans’ seventh climax of the night grip his cock like a vise, forcing him to spill once more into his brother’s throbbing pussy with a  groan. Sans whimpered and moaned under him, his whole body rendered boneless (heh) by the insane sex the other had unleashed on him. Papyrus took a moment to soak in the sight of his brother’s flushed face, cheekbones streaked with pleasured tears and the line of drool that dripped from his chin. Papyrus leaned forward to nuzzle at his exposed neckbones, lathing the sensitive vertebrae with his tongue as he withdrew his cock from Sans’ cunt only to press back in again. Sans jerked and gasped at the renewed thrusting, managing to weakly push at Papyrus sternum.

“p-please paps… i-i can’t-” His words were halted as Papyrus pressed his mouth against his brother’s, swallowing the moans and pleas while his thrusting grew more haggard. Papyrus’ tongue slid across Sans’ as he pumped his hips, moaning into the warm mouth and listening to the erotic sound of fluids squelching around his cock as their hips met with a clack. Sans tensed up again, a chocked scream swallowed by Papyrus’ mandible when he climaxed for the final time, his walls somehow finding the energy to grip and pulse around his brother. Papyrus’ hips stuttered once more at the feeling, sheathing himself fully inside Sans and cumming with a gasp.

Finally his heat was over. Papyrus panted and shivered, his mind clearing and the electric aftershocks of his most recent climax steadily melting away into a pleasant afterglow. Exhaustion plagued him. He wanted nothing more than to crawl under the covers and sleep for at least five hours. Opening his eyesockets he quickly checked Sans, worried that his rather overzealous performance might have injured his smaller lover. His fears were unfounded as Sans’ snores reached his nonexistent ears, the check proving that Sans’ HP was still at his full one and he was happily asleep. The flavor text did mention something about not being able to walk straight for two days but Papyrus chose to ignore that for now.

Papyrus gently maneuvered them both under the covers, curling around his older brother and smiling at the way he fit just right against him. Sans murmured in his sleep and instinctively grasped at the taller skeleton’s ribs while nuzzling closer to his warmth. Papyrus clutched Sans tighter and sighed deeply, fluttering his eyesockets shut and letting the sweet embrace of sleep begin to claim him. He would have to cook Sans a wonderful breakfast for helping him through his heat. He wondered if Sans would like ketchup on his pancakes?

**Notes for the Chapter:**

> need sleep.........

**Author's Note:**

> Comment, critique, tell me what ya thought.  
> 


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